LIBRARY OF CONGRESS. 

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UNITED STATES OF AMERICA. 



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Boston g>octetp of jfMural iptstorp. 



GUIDES FOR SCIENCE-TEACHING. 

No. II. 

Concerning a few Common 
Plants. (Part i.) 

By GEORGE L. GOOD ALE. 



BOSTON: 

PUBLISHED BY THE SOCIETY. 

1879. 



Boston g>octetp of Batural ^tstorp. 



GUIDES FOR SCIENCE-TEACHING. 

No. II. 

Concerning a few Common 
Plants. (Part i.) 



By GEORGE L. GOODALE. 



/C i 






-/ 



BOSTON: 

PUBLISHED BY THE SOCIETY. 
1879. 



'/. 1 P' r O ^ // 



C*.5V> 



Copyright, 

By the Boston Society of Natural History.. 

1879. 



reV^y 



Cambridge : 
Press of John Wilson and Son. 



INTRODUCTION. 



The botanical lessons in the Teachers' Course in 
Science, for 1878-79, are given at that period of the 
year which is most unfavorable for the selection of 
illustrative material. During the preparation of the 
lessons under this serious disadvantage, and while the 
choice of objects for study was still under advisement, 
it became clear that a few printed details respecting 
the illustrations and their use would be of service to 
the teachers in attendance upon the course. 

At the same time, a fear was felt that such a printed 
supplement might perhaps restrict the application of 
the methods of study recommended, by binding some 
teachers to the use of only the scanty materials here 
employed. It is, therefore, with some misgivings that 
the supplement has been prepared. The design of the 
lessons is to point out one method by which a few of 
the more important and easily observed facts can be 
taught, respecting the structure, growth, and work of 
plants ; while the purpose of this guide is to call atten- 
tion to the manner of preparing the objects selected 
for such elementary study, and to furnish some sugges- 
tions as to the way they can most readily be turned to 



6 INTRODUCTION. 

good account. It must not be forgotten that in au- 
tumn, spring, and summer, more abundant material 
for study is at hand, and the range of choice is at those 
seasons very wide. Therefore, the present outline must 
be looked upon as one which a judicious teacher can 
change for the better : every object for study may be 
replaced by others ; and the sequence in which the 
objects are examined may be modified, provided the 
pupils are induced to observe for themselves, to com- 
pare for themselves, and, in short, to do their own 
thinking. The teaching, which is advised in this 
course of botanical lessons, is based upon the belief 
that the pupil must earn his facts ; that, in general, 
facts which a pupil may acquire for himself are to be 
placed within his reach, but not in his hands. He 
must make some exertion to get knowledge, in order 
that it may become his. But in what way can a pupil 
be led to exert himself? Certainly not by having 
every thing done for him. 

In applying this general statement to the case in 
hand, it may be said, first, that the interest which chil- 
dren take in the more attractive plants around them, in 
the brilliancy and varied shapes of flowers, and in the 
growth of seedlings, should be increased by every 
means at the teacher's command. 

It may be remarked, secondly, that the information 
which the teacher imparts respecting plants in which 
the child is interested should be furnished with the 
ultimate design of leading the pupil to observe for him- 
self ; and, with tact, this can be done even with the 
youngest. Answer all questions which the pupil can- 
not answer for himself by careful examination of the 



INTRODUCTION. 7 

plant before him, but do not sjiow him what he ought 
to see with his own eyes, and without help. 

The successful attempts made by the late Professor 
J. S. Henslow, of Cambridge, England, to introduce 
botanical study into the parish and common schools, 
are doubtless known to many readers of this guide ; but 
it may not be so widely known how far that model 
teacher insisted upon self-help. 

In his " Practical Lessons on Botany," * Professor 
Henslow makes use of the following language : — 

" In order to employ Botany as a strictly educational 
weapon, we must not confine ourselves to telling chil- 
dren the names of plants, how they may be artificially 
grouped, what properties they possess, or the few physi- 
ological facts hitherto established with more or less 
precision respecting them. We may give any one val- 
uable instruction of this description, either orally or by 
books, without having exacted the requisite attention 
to the structure of plants which demands a personal 
observation of facts, and a decided mental effort to 
derive just inferences from that kind of circumstantial 
evidence which such facts afford in regard to their 
affinities. Experience has satisfied me that ' Structural 
Botany ' may be more conveniently and extensively 
employed than any other branch of natural science, for 
strengthening the observant faculties and expanding 
the reasoning powers of children in all classes of 
society." 

He further says, f — 

* Illustrations to be employed in Practical Lessons on 
Botany, adapted to Beginners of all Classes. Prepared for the 
South Kensington Museum, by the Rev. Professor Henslow. 
London : Chapman & Hall. 1858. 8vo, 31 pp. 

t p. 28. 



8 INTRODUCTION. 

" Our present object has been to deal merely with 
the rudiments of that department of the science which 
seems, above all other branches of natural science, best 
adapted for educational purposes. These are, indeed, 
replete* with difficulties hard to be overcome by inat- 
tentive, unobservant minds, but can be mastered with- 
out more than ordinary, wholesome painstaking, even 
by young children." 

The " wholesome painstaking " here referred to is 
thought to be an important element of success in oral 
teaching. The pupil is not to be a passive recipient. 
The teaching is not to be a " pouring in : " it is simply 
giving the thirsty a chance to drink. 

The fact is often deplored that some pupils make 
only an indolent and trifling use of the information 
given them by their teachers. Is it not a pertinent 
question, whether the fault may not arise from the 
unwise manner in which the information is imparted. 
Is it not too often given to the pupil, without any 
exertion of his own? Lavish gifts cannot make the 
recipient thrifty : they tend to make him a spendthrift. 
A possible danger of oral teaching, and much other 
teaching, for that matter, comes from this very source ; 
namely, an injudicious giving of what should be 
earned. To guard against this danger in the limited 
field now before us, every teacher should clearly un- 
derstand what facts are within the pupil's reach, and 
which he must work to acquire. But there are facts 
which lie at the side of the path pursued in the study, 
and which may be freely furnished by the teacher, if 
they heighten interest in the task. If they fail to in- 
crease the interest, or if they distract in any way, it 



INTRODUCTION. 9 

is because they have been injudiciously selected, or 
presented at an unpropitious time. Let it not be for- 
gotten that oral teaching is not like cross-tag, a game 
in which the object pursued must be abandoned foi 
the first thing which comes between. 

For the purpose of assisting teachers in their work, 
this little guide has been made as plain and as full as 
the narrow limits allow. 

The cultures and experiments, of which details are 
given, can be managed in any school-room, without 
encroaching seriously upon the leisure of a faithful 
teacher. The care of the growing plants, and the 
daily observations of changes in their form and kinds 
of work, should devolve upon one or more of the 
pupils. Even the slight errors which may be at first 
made by the young observers and experimenters, and 
the trifling failures which will result therefrom, can be 
turned to good account. The time occupied by most 
of the cultures is so short that frequent repetitions 
will be found practicable and desirable ; and the dis- 
crepant results will often furnish fresh and interesting 
material for study. The appliances which are here 
recommended are of the most trifling cost. Even 
simple lenses are not absolutely required for any of 
the studies here suggested. 

To anticipate a question often asked, it may be said 
that the treasuries of interesting facts in Botany upon 
which a skilful teacher can draw at discretion in talks 
about plants are very numerous. Besides the Ameri- 
can treatises referred to in this guide, the following 
may be mentioned : — 



IO INTRODUCTION. 

Lessons in Elementary Botany. By Prof. Oliver. Mac- 
millan & Co. : London and New York. This is a duo- 
decimo volume, based upon the manuscripts left by Prof. 
Henslow. This would answer every purpose. 

A System of Botany. By Le Maout and Decaisne. Trans- 
lated from the French by Mrs. Hooker. A quarto volume 
of about a thousand pages. 

A Class-Book of Botany. By Prof. Balfour of Edinburgh. 
An octavo of about a thousand pages. 

Thome's Botany. Translated from the German by A. W. 
Bennett. An excellent translation of a very useful book. 



CONCERNING 
A FEW COMMON PLANTS. 

Part I. 



I. SEEDLINGS AND SEEDS. 

I. A STUDY OF THE PARTS OF ONE SEEDLING, AND THEIR 
RELATION TO THE PARTS OF A SEED. 

A couple of quarts of clean sea-sand in small flower- 
pots, or in shallow glasses, or in deep plates, will 
answer for the garden. The best seeds to begin with 
are beans and peas. The variety known as Horticul- 
tural Bean is large, and adapted to the purpose ; but 
common White Beans will do about as well. Any of 
the ordinary varieties of Garden Peas may be employed. 
Two ounces of Beans and one ounce of Peas will be 
an abundant supply. 

Let the pupils plant a dozen seeds of each sort half 
an inch deep in the moist sand, and place the flower- 
pots containing them on a table where the temperature 
will be about 65 ° or 70 Fahrenheit. It is a good plan 
to have the flower-pots covered at first by a pane of 
glass, in order to keep the sand moist. The pupils in 
charge of these cultures should take good care lest 
the sand becomes dry. When the seedlings start, 



12 CONCERNING A FEW 

which will usually be in two or three days, a second 
lot of seeds should be planted, and in two days more 
a third. The care of the seedlings ought to fall upon 
the pupils, and not directly upon the teacher. It will 
be generally found that this trifling care is willingly 
assumed. At the end of a week or ten days, the 
seedlings will all be growing well. When the largest 
seedlings are four or five inches high, the suite of 
specimens will range from seeds just starting up to 
those with three or more green leaves. To complete 
the set, let a dozen seeds of both kinds be soaked in 
water, a day before the first systematic study of the 
plants. The bean-plants are to be carefully removed 
from the sand, and arranged by the pupils, who will 
place them in a series running from the largest 
series, down to the smallest, the latter being, of course, 
the soaked seeds which have not germinated. 
With the series before him, the pupil may be left to 
himself to study out the differences and the points of 
likeness ; but, in general, it will be found better for 
the teacher to guide the work by asking a few simple 
questions, which must be answered by an examination of 
the plants. The questions may first bear upon the differ- 
ences between the largest, the middle-sized, and the 
smallest plants, in order to bring out the changes which 
have taken place by growth. It will be seen at once 
that the pupil begins to match the parts which corre- 
spond to each other, and that he can identify the parts 
of the seedlings with their rudiments in the seed. He 
will trace back the roots of the plants to the tip of the 
cone-like body in the seed : the shrivelled and greenish 
seed-leaves are seen to be the withering halves which 



COMMON PLAXTS. 13 

made up the bulk of the seed ; the stem below these 
and the stem above, with its green leaves, are identified 
with their promise in the seed itself. He will see for 
himself how the seedling escaped from its integuments, 
and in what order its parts have successively appeared. 

It is a good plan to have a few other seedlings of the 
same sort raised in a slightly different way ; namely, 
upon wet paper. These seedlings are wholly free from 
sand, and may serve to make the series a little more 
complete. For paper planting, use thick blotting-paper 
on a pane of glass. The paper is to be thoroughly 
moistened with warm water, and upon it a few seeds of 
each kind are to be placed. These are to be covered 
by a moist sheet of paper like the lower one, and the 
whole kept warm and damp. A damp sponge, or wet 
cotton-batting, or moist sawdust, would be just as good 
a support for the seeds : the seeds need warmth, 
moisture, and access of air, and these conditions are 
furnished by any of the materials mentioned ; but the 
sand and the paper will be found in practice to be most 
convenient and cleanly. Another method of raising 
the seedlings may be mentioned at this point. After 
the seed has sprouted on wet paper, suspend it care- 
fully by a thread, or upon a perforated card, over water 
in a tumbler or glass vase, so that the roots dip beneath 
the surface, while the seed-leaves remain held above. 
The roots will spread through the water, and the leaves 
will expand in the air. An acorn or a grain of corn 
treated in this manner will be watched with great 
interest. 

When the pupil has made himself familiar with the 
development of the seedling beans, and has compared 



14 CONCERNING A FEW 

their parts with the corresponding parts of the seeds, 
he is prepared to examine in the same way the 

series.** seedlings of the pea. The sequence of points 
observed may be the same as before, but 

never let any order degenerate into a monotonous 

routine. 

2. COMPARISON OF TWO SEEDLINGS. 

After this examination has been made, the compari- 
son of the plants of bean and pea is to be undertaken. 
In some particulars the plants resemble each other 
closely, in other characters they are very different. 
The differences and the points of likeness are all to be 
brought out clearly, so that the following questions can 
be answered from the student's examination of the 
plants : — 

i st. What are the differences between the parts of 
the larger and the smaller plants of the same kind ? 

2d. What are the differences between the two kinds 
of plants, the seedling bean and the seedling pea ? 

3d. What do the seedling bean and the seedling 
pea have in common ? 

Each of these questions must of course be much 
divided, in order to ascertain whether the whole sub- 
ject has been thoroughly examined by the pupil. The 
character of the subordinate questions must be care- 
fully adapted by the teacher to the capacity of the par- 
ticular class of pupils. Just at this point, it must be 
said that the task of observing, comparing, and judging, 
may be made attractive by the teacher, or it may be 
made irksome, depending on the kind of questions 
asked. The child will be interested in the work, if it is 



COMMON PLANTS. 15 

not made too easy, if the questions are so designed 
and arranged as to stimulate curiosity instead of weary- 
ing the mind. 

It will be asked by some teachers, whether it would 
not be well to furnish technical terms to the pupils at 
the beginning of their study. The late Professor 
Henslow believed that the ordinary botanical adjectives 
and nouns should be employed at the outset. His 
views upon this subject are very clearly stated in the 
following extract from the educational work previously 
referred to : — 

" In order to secure a beneficial result of this sort," 
that is, to strengthen the observant faculties and 
expand the reasoning powers of children, " we must 
not avoid the use of certain technical expressions, 
however pedantically unnecessary they may appear to 
persons unacquainted with their importance and unac- 
customed to their use. Scientifically accurate ideas 
must always be conveyed either by entirely new words 
or by peculiar technical meanings assigned to old words. 
Botanists employ both methods. Some of the most 
important technical terms have not been judiciously 
selected. Some are too long, others harsh and un- 
grammatical. But the few terms to which these objec- 
tions apply cannot be satisfactorily dispensed with. 
They are thoroughly established, and are, in fact, much 
more readily learned than might be imagined." 

Professor Henslow's first step in the instruction of his 
class of children was to place before them the follow 
ing words to be correctly spelled from memory : — 



1 6 CONCERNING A FEW 

Class. Division. Section. 

(I. Exercise.) (II. Exercise.) (IV. Exercise.) 

{I. Thalamifloral. 

2. Calycifloral. 

3. Corollifloral. 

4. Incomplete. 
I 2. Gymnospermous. 

(III. Exercise.) 
f 1. Petaloid. i Superior. 

2. Monocotyledons. <( ( mtenor. 

[ 2. Glumaceous. 

3. Acotyledons. 

One part of each Monday lesson consisted of a 
Hard-word Exercise. "Two or three words named 
one Monday are to be correctly spelled the next Mon- 
day." 

This must be called an extreme method, and, at first 
sight, it would be called an impracticable one ; but, 
judged by its results, it is admirably adapted to some 
classes of pupils. (In a most useful adaptation and 
amplification of Professor Henslow's system of botan- 
ical teaching, Miss Youmans * has pursued a very judi- 
cious course. The technical terms are not thrust upon 
the student : they are introduced only as they are 
needed in recording the results of observation.) In oral 
instruction, however, it would seem to be better to let 
the technical terms come only when they can be of as- 
sistance to the student, and felt to be aids in his work. 
Technical words are short-cuts across tiresome circumlo- 
cutions. Children can be early made to feel that much 
is gained by their appropriate and timely use ; but, in the 

* The First Book of Botany, designed to cultivate the ob- 
serving powers of children. By Eliza A. Youmans. New 
York. 



COMMON PLANTS. 17 

simple studies of plants here recommended, the employ- 
ment of technical substantives and adjectives can be for 
the most part avoided. In the case of the youngest 
pupils, this avoidance of such terms should be regarded 
as very necessary : the term must never come between 
the child and the thing or the phenomenon studied. 



3. VERY DIFFERENT SEEDLINGS COMPARED WITH 
EACH OTHER. 

To procure material for this purpose, plant in the 
manner before directed a few seeds of Squash, Morn- 
ing-glory, and Water-cress, and a few of the seed-like 
fruits (commonly called " seeds") of Sunflower, In- 
dian corn, Four-o'clock, and Wheat. The cress-seed 
need not be placed below the surface of the sand. 
When any of the seedlings have fairly started, let a 
second set of the seeds of the same be sown, and, when 
the latter have sprouted, plant a third set. Each 
kind of seedling is to be examined after the series, 
manner fully detailed with respect to the bean, 
and all its parts are to be matched with the parts seen 
in the seed. Afterwards let these different kinds of 
seedlings be carefully compared with each other, and 
with such seedlings of the bean and pea as may have 
been left over. The differences in development are 
plainly seen, the points of likeness are not so obvious, 
but their recognition must be insisted upon. The child 
must be led by questions, never by statements, to see 
the resemblance between the seedlings before him. 
If this is honestly and patiently tried, it will be found 
that the child, by a decided mental effort, will detect 



1 8 CONCERNING A FEW 

what the seedlings have in common. He will see that 
in some cases the seed-leaves have become pretty good 
green leaves, that in others they are shrunken and green- 
ish, that in others they do not come into the light. He 
will notice also differences in number as well as shape. 
By adroit questions, the teacher can lead the pupil up 
to the examination of what the seed-leaves can possibly 
be for, and without furnishing any aid to the investi- 
gator elicit at last the suggestion that they may be food- 
leaves for the young plant. Some young plants begin 
to earn their own living very early, others have a good 
store laid up for them, and this store of food is put in 
different places, and is of different kinds. Let 
of seed- the food be searched for in the Four-o'clock and 
ings ' Corn and Morning-glory • and, when the pupil 
has made out this for himself, the other kinds of food 
which seedlings have may be described as the teacher 
may have leisure. The food of the vegetable-ivory seed- 
ling, which is as hard as ivory itself ; the food of the nut- 
meg-seedling, the aromatic substance which makes up 
the bulk of the seed ; and other sorts of food, — can fur- 
nish material for a talk which would not be uninterest- 
ing even to the dullest pupil. The oily food of flax- 
seedlings can be shown in some crushed flax-seed 
placed between dry blotting-paper. The linseed oil 
will appear in the paper. The very different food of 
wheat-seedlings may be exhibited best in very fine 
flour. The flour is to be slightly moistened in the hand 
and kneaded until it becomes an homogeneous mass. 
Upon this mass pour some pure water, and wash out 
all the white powder until nothing is left except a viscid 
lump of gluten. This is the part of the crushed wheat- 



COMMON PLAXTS. 19 

tins which very closely resembles in its composition 
the flesh of animals. The white powder washed away 
is nearly pure wheat-starch. Of course, the other 
ingredients, such as the mineral matter and the like, 
might be referred to ; but the starch, at least, should 
be shown. When the seed is placed in proper soil, or 
upon a support where it can receive moisture, and can 
get at the air, and still be warm enough, a part of the 
starch changes into a sort of gum like that on postage- 
stamps, and finally becomes a kind of sugar. Upon 
this syrup the young seedling feeds until it has some 
good green leaves for work ; and, as we have seen in 
the case of some plants, it has these very early. 

The starchy food in seeds keeps good a long while, 
and seeds having such food will grow, even after they 
have been kept for many years ; but the oily seeds are 
apt to spoil much sooner. The food in the seed is 
packed away in minute compartments (cells), and is 
used by the seedling in making new compartments for 
different kinds of work. How the starch was made for 
and put into the seed, and how it is used in growth, 
will be . seen later on. 



II. HOW THE PARTS OF FLOWERING PLANTS 
HELP ONE ANOTHER. 

This guide is devoted to the consideration of only 
the flowering plants, those which have true blossoms 
and bear seeds with plantlets in them. Therefore, 
mosses and their kindred are not now treated of. If 
any of the seedlings spoken of in 1, 2, or 3, be carefully 
examined when it has a few green leaves, it will be 



20 CONCERNING A FEW 



f*„v 



seen to be made up of roots, stem, leaves, and a few 
delicate plant-hairs. Now these are all the parts that 
any flowering plant ever has : the thorns and tendrils, 
and showy leaves and blossoms, and all the parts of 
every blossom, are only modified forms of one or more 
of the four parts or members just spoken of. This is 
the statement, made abruptly and in few words-, of the 
accepted theory of plant structure. Of course it is 
difficult to bring such an abstruse notion before a child; 
but, inasmuch as the notion itself is of great assistance 
even in a very rudimentary study of common plants, 
the endeavor ought to be made. The attempt has 
been successfully made in the following manner : The 
several series of older seedlings with plenty of leaves 
and good roots are to be placed before the pupil with 
some such question as this : How many times are parts 
which are made up of a joint of stem, and a green leaf 
above, repeated in each plant ? In one, there will be 
six or more of these repeated parts ; in another, only 
two or three ; in another, perhaps only one. That the 
" repeated parts " differ greatly in their shape has been 
noticed in the study of the seedlings ; that the re- 
peated leaves have different kinds of work was also 
then made plain. If this is clearly understood, the 

pupil may be told that these " repeated parts " 
iwts. mg are helpiiig parts or helpful parts. These parts 

are mutually helpful : they help one another. 
The whole plant is made up of just such parts, which 
have taken different forms for different kinds of work, 
as, for instance, in the leaves of the pea. It has been 
found that children grasp this notion of the helping- 
parts very readily, and hold it very firmly, as an aid in 






COMMON PLANTS. 21 

their further progress. (Although it would be advisa- 
ble in the case of the older pupils to bring out clearly 
the notion of the phyton, or phytomer, the internode 
of stem with its node and leaf, it is generally better to 
state that the helping parts are joints of stem with the 
leaf which belongs to it, and that any one of these 
helping parts may have roots and hairs, and, further, 
that they take very different forms for different kinds 
of work.) 

The seedlings have shown these helpful parts, ar- 
ranged in regular order. From the lowest of the help- 
ful parts of the bean, the root started ; but, in the 
Indian corn, roots have started off higher up. Again, 
they have plant-hairs in different places. Upon the 
youngest rootlets of the wheat or corn planted on wet 
paper, the hairs are very abundant ; and there are some 
hairs scattered on the leaves of the bean. These roots 
and the hairs are to be examined later. 

The succession of the helpful parts will be noticed 
best in slips of the common plants, "Wandering Jew," 
or Tradescantia, Heliotrope, and Bouvardia. In the 
case of the Tradescantia, the growth of a slip or cut- 
ting in moist sand, or with the lower end in water, is 
very instructive : roots grow from the lowest of the 
helpful parts, and furnish the food needed in solution, 
new leaves expand above to get food, as we shall 
see, from the air: and thus a separate, self- 

n Commu- 

supportmg colony is established. A flower- nitiesand 
ing plant is a community from which many 
such colonies might be removed. 

Next, the pupil should be led to study the question : 
Where do these helpful parts come from? For this 



2 2 CONCERNING A FEW 

purpose, a good branch of Horsechestnut, stripped of 
its leaves, but having large buds, will be found useful. 
This should be studied without any help from the 
teacher ; in fact, if any aid is asked for, it may be 
accepted as an indication that the pupil has made too 
great haste and to very little purpose. A child who has 
patiently gone through the examination of the seed- 
lings will be able to see that the bud-scales are leaves, 
changed in form, to be sure, but not so much as some 
of those in the seedlings, and that these leaves are 
regularly but closely packed upon a tiny space from 
which the stem is to grow in the spring. In many of 
the larger and more plump buds of horsechestnut, the 
rudimentary flower-cluster can be seen. Next, ask the 
pupil how old a fragment of a branch with a terminal 
bud is ; and, if he has fully grasped the idea that a bud 
is the promise of a branch, he will count back and see 
how many rings of bud-scale scars there are on the 
stem. The clusters of rings mark the years. 

In the buds of Lilac, the four-sided character of the 
bud will probably attract attention. Any of the large 
buds of our deciduous shrubs and trees will present 
many interesting features for examination ; namely, the 
relative size, position normally in the upper angle which 
a leaf makes with the stem, the protective scales or 
outer parts, the mode of packing, and the presence or 
absence of flowers within. It must not be supposed 
that the subject of buds can possess as much interest 
for younger as for the older pupils ; nor will it be found 
for the latter as interesting as the studies of seedlings 
and flowers. But, nevertheless, with the exercise of 
some tact, good use can be made of the abundant 






COMMON PLANTS. 23 

material for study which our common buds afford. In 
winter, or better at the approach of spring, shoots with 
strong buds can be kept fresh for a long time by dip- 
ping the lower end of the cutting in water, and some- 
times the buds will develop good leaves. Shoots of 
Rhodora and Cassandra having flower-buds will bloom 
after a few weeks' exposure to the warm air of a room, 
provided the cut ends are not allowed to dry. And 
this brings up the allied subject of flower-buds and 
what they teach. Procure for the purpose of this study 
good flower-buds of any common house-plant \ and 
with these give the pupils large leaf-buds of Lilac or 
Horsechestnut for examination and comparison. Most 
of them will soon remark upon the regular though dif- 
ferent arrangement in the various parts of buds, and 
recall the fact that a bud is the promise of a branch. 
The application of this to the case in hand will force 
the conclusion that, since whatever springs from a bud 
is some sort of a branch, a developed flower from a 
flower-bud must be a branch too. And so it is. The 
helpful parts are here arranged in a very regular manner, 
and many of them are greatly changed in form and 
in work. From this subject, to be examined fully in 
another place, we pass naturally to the development of 
buds underground. A leaf-bud — that is, an incipient 
stem — develops by lengthening the distance between 
the successive leaves. Under ground, in firm soil, such 
buds develop at great disadvantage ; and the stems 
soon become more or less distorted, the degree of dis- 
tortion depending somewhat upon the character of the 
soil in which growth takes place. The extremes are to 
be found in Beach Bind-grass {Calamagrostis arenaria) > 



24 CONCERNING A FEW 

which has long internodes or joints of stem, and such 
plants as Iris, or Blue Flag, and Solomon's Seal. In not 
a few cases, the growth of the underground stem gives 
rise to very curious forms, which may be puzzling at first ; 
for instance, the solid bulb or corm of crocus, and the 
thickened tip of the underground branch of potato, 
namely, the tuber itself. The " eyes " of the potato are 
merely disguised buds which have a good stock of food 
behind them. Potato -planting is colonizing, in which 
the tubers are the colonies separated from the home 
community. A very bad kind of such colonizing takes 
place when the underground stems of Witch-grass 
( Triticum rep ens) are only broken off, but not taken out 
of the soil, in hoeing the ground. The helpful parts are 
detached from each other, and each fragment serves as 
a starting point for a new plant. In grafting and in 
budding, one or more groups of colonies of helpful 
parts are removed, not to soil where they would have 
at once to shift for themselves, but to a kindred plant, 
which furnishes proper nutriment from the very first. 

Thus, it will be seen that from a few kinds of buds 
children may learn a good many things. They will 
clearly apprehend the notion that buds consist of help- 
ful parts which are packed away in a rudimentary form ; 
and they will, after a little, recognize buds under their 
many disguises in bulbs, bulblets, and the like. When 
they have made this out, they will next proceed to learn 
that buds are formed as a rule in the axil * of leaves, 
and that whatever grows from a bud is a branch of some 
sort ; all of which facts can be learned by observation, 
and not merely told to the pupil. 

* That is, the upper angle formed by the leaf and the stem. 



COMMON PLANTS. 25 

III. ROOTS. 
I. THEIR MODE OF GROWTH. 

As we have seen in the examination of seedlings and 
cuttings, roots can start from different points of the 
stem. In some cases, they can arise from the leaf-stalk 
or even from the leaf-blade itself. The root, whatever 
its origin in any case may be, grows in length only in 
one way ; namely, at a point just behind its very tip. 
This growing point is usually protected by a peculiar 
cap, which insinuates its way through the crevices of the 
soil. If roots should grow as stems escaping from the 
bud-state do, — that is, throughout their whole length, — 
they would speedily become distorted. But, since they, 
grow at the protected tips, they can make their way 
through the interstices of soil, which from its compact- 
ness would otherwise forbid their progress. 

That roots grow in length only in this way can be 
easily proved by a simple experiment, which can be left 
to the management of any pupil. Let a young TT 

r , \ • 1 How roots 

seedling of corn be grown on damp paper m the grow in 
manner described in 1, and, when the longest 
root is a few centimetres long, let it be marked very care- 
fully by means of India ink or purple ink, put on with 
a delicate camel's-hair pencil, by lines just one centi- 
metre apart. The plants thus marked are to be kept 
under favorable conditions with respect to moisture and 
warmth, so that growth will be as rapid as possible. 
The marks on the older part of the root will not change 
their relative distance, but the mark at the tip will be 



26 CONCERNING A FEW 

carried away from the one next to it, showing that the 
growth has taken place only at this point. Such experi- 
ments as the one just described are perfectly practica- 
ble for all classes of pupils except the very youngest. 
How far the details of these experiments should be 
suggested to the pupils, or rather how far they should 
be left to work out the problems for themselves, is a 
question to be settled by the teacher in each case. 
The better plan generally is to bring the problem in a 
very clear form before the whole class, or before the 
whole school, and ask whether anybody can think of a 
way in which it can be solved ; for instance, in this case 
how can it be found out whether roots grow only at 
their tip or throughout their whole length. If the way 
is thought out by even a single pupil, the rest will be 
interested in seeing whether the plan will work success- 
fully. The conditions which govern the growth of 
roots in length may be made a very attractive study, by 
leading the pupils who are for the time in charge of the 
experiments to race the root-tips. The quick-witted 
experimenters will soon learn the best degree of warmth 
and the requisite amount of moisture for improving the 
time made by the root-tips under their care. 

The branching of roots never seems very symmetrical 
at first sight, but that there is sometimes an obscure 

order underlying the arrangement can be made 
^r c h?° ts c ^ ear by the water culture referred to under i. 

Concerning the thickening up of roots as store- 
houses of food, nothing will now be said. 



COMMON PLANTS. 2 J 

2. THEIR WORK. 

If the roots of the youngest seedlings of wheat or flax 
are carefully examined, they will be seen to be covered, 
except near the tip, by a very delicate fuzz 
made up of extremely fine hairs. These are ^irs" 
the root-hairs, which serve to take up the water- 
food for plants. They are so exquisitely delicate that 
the slightest touch- crushes them ; and, if the plant is 
lifted from the soil, the root-hairs are left behind, or 
else a few hold fast to finer particles of soil which are 
brought away. 

Of course, a microscope is very necessary in any 
careful examination of root-hairs ; but the hairs can be 
seen without one in the cases mentioned, and in some 
others, where they are looked for carefully. The pupils 
may be told that it is these root-hairs, and not the very 
tips of the roots, which absorb water. This can be 
studied practically by the older pupils in the way 
pointed out by Ohiert, a German school-teacher, who 
first published, in 1837, an account of root-hairs. 
The tips may be carefully removed, and the wounds 
painted over, and the roots be placed again in water, 
where the hairs can have a chance to absorb, if this is 
their office. 

Root-hairs are found only on the newer parts of 
roots ; and these are therefore the only active ab- 
sorbents of dilute aqueous solutions. 



28 CONCERNING A FEW 

IV. LEAVES. 

The dilute solutions just spoken of are carried through 
the older parts of the root up to the stem, and through 
the stem to the leaves and other green surfaces. Here 
some very interesting changes take place, a few of 
which can be made plain, even to the young children 
who have faithfully worked out the subjects up to this 
point. 

Green leaves are generally so constructed that water 
evaporates readily from their substance. This exhala- 
tion (although it is something more than mere evapo- 
ration) can be shown by a very simple experiment, 
devised by Professor Henslow, and which will be de- 
scribed in the words of Professor Oliver's Botany, 

p. is- — 

" Exposure to sunlight, as well as dryness of the 
air, has to do with this evaporation of water from 
the leaves. Take six or eight of the largest, healthiest 
leaves you can find, two tumblers, filled to within an 
inch of the top with water, two empty, dry tumblers, 
and two pieces of card, each large enough to cover 
the mouth of a tumbler. In the middle of each card 
bore three or four small holes, just wide enough to 
allow the petiole of a leaf to pass through. Let the 
petioles hang sufficiently deep into the water when 
the cards are put upon the tumblers containing it. 
Having arranged matters thus, turn the empty tumblers 
upside down, one over each card, so as to cover the 
blade of the leaves. Place one pair of tumblers in 
the sunshine, the other pair in a shady place. In five 
or ten minutes, examine the inverted tumblers. That 



COMMON PLANTS. 29 

exposed to the sun you will find already lined with 
dew on its cool side, while that kept out of the sun is 
still nearly or quite clear. It is manifest, therefore, 
that evaporation from the leaves must be not only 
rapid, but considerable in amount, when plants are 
exposed to the sun or a dry atmosphere." 

By the evaporation, or transpiration, as it is called, 
which goes on from green leaves, the dilute solutions 
which have been raised to the foliage become more 
concentrated. The transpiration is governed largely 
by delicately balanced valves, which are chiefly on the 
under surface of the leaves. 

Whether it is best to try to explain to the pupils the 
structure of these valves, or stomata, must be left to 
each teacher. 

It would seem advisable to pass by the subject un- 
touched, unless the teacher has become reasonably 
familiar with it by practical microscopical study of 
leaves. For a teacher to endeavor to explain the 
complex structure of the leaf, without having seen 
it for himself, is open to the same objection which 
could be urged against the attempted explanation of 
complicated machinery by one who has never seen it, 
but has heard about it. What is here said in regard to 
stomata applies to all the more recondite matters con- 
nected with plant structure. 

Within the tissue of green leaves, there can be found 
under the microscope granules of a leaf-green 
substance called chlorophyll. Under the infra- v ^ r a k f ~ 
ence of sunlight, carbon dioxide, a gas which 
exists as an impurity in the atmosphere, and which 
is readily taken up by green leaves, undergoes, together 



3° CONCERNING A FEW 

with the water within the leaf, changes which end in 
the formation of starch or something very much like it. 
While such an operation is going on, oxygen is given 
off by the leaves. The relations of oxygen and carbon 
dioxide to animal respiration are to be pointed out to 
the pupils ; and it is to be made clear that the evolu- 
tion of oxygen from green leaves goes on only in the 
light. In all its kinds of activity, except that of leaf- 
green work with gases, the plant takes in oxygen and 
gives off carbon dioxide. But the work of leaf-green 
in sunlight, namely, the conversion of inorganic matter 
into organic substance, is the chief work of the com- 
mon plants about which we have been studying. This 
work is assimilation. The description of this process, 
and its relations to growth, are very clearly stated in Dr. 
Gray's " How Plants Grow," and in his " Lessons in 
Botany." 

The assimilated product made by green leaves in 
sunlight is stored up in many forms and in many places, 
such as roots, stems under and above' ground, leaves, 
and seeds. It is used for many purposes, chiefly the 
following : making wood, and the like, building up new 
parts, forming flowers, and making seeds. Some of 
these kinds of work are to be briefly examined. 

To sum up the work of green tissues, whether on 
the stem or in leaves themselves, it may be said that 
they lift dilute solutions from the roots to the light and 
air, thus concentrating them ; that they are the facto- 
ries where starch or something very similar is made. 
To point out the many beautiful adaptations to these 
purposes by different exposures, positions, and shapes, 



COMMON PLANTS. 31 

will furnish to every teacher conversant with the facts 
very abundant material for interesting talks. 

The remaining portions of the guide will consider 
the subjects of wood-making, the storing of food, the 
structure of blossoms, and the office of the latter in 
building seeds, and lastly the formation by the plant of 
new products, some of which are useful, some of which 
are injurious to man. 



Cambridge : Press of John Wilson <5r» Son. 



Boston g>octetp of iQaturai ^tstarp. 



GUIDES FOR SCIENCE-TEACHING. 

No. II. 

Concerning a few Common 
Plants. (Part ii.) 

By GEORGE L. GOODALE. 



BOSTON: 

PUBLISHED BY THE SOCIETY. 
1879. 



CONCERNING A FEW COMMON PLANTS. 



Boston Society of iQatural I^istorp* 



GUIDES FOR SCIENCE-TEACHING. 

No. II. 

Concerning a few Common 
Plants. (Part ii.) 






By GEORGE L. GOODALE. 



• /C 

V,J879 ^ 



BOSTON: 

PUBLISHED BY THE SOCIETY. 

1879. 



Copyright, 

By the Boston Society of Natural History. 

1879. 



Cambridge: 
Press of John Wilson and Son. 



CONCERNING 
A FEW COMMON PLANTS. 

Part II. 



V. SOME OF THE RELATIONS OF PLANTS TO 
THE SOIL. 

When the trunk of a tree or the stem of an herba- 
ceous plant is carefully burned in the open air, there 
remains behind a certain amount of rusty-gray 
ashes. This substance represents the mineral ™hes." 
matters taken in solution by the roots, and now 
changed somewhat by combustion. Some plants con- 
tain more of this mineral matter than do others, but all 
of them have a trace ; and there is a substantial agree- 
ment in the chemical elements of the ash of different 
plants. Some of the elements which have been de- 
tected in the ash are Iron, Potassium, Calcium, Mag- 
nesium, Phosphorus, and Sulphur. These exist in 
composition in the ash, — for instance, the Potassium is 
there a carbonate ; but as to the manner in which they 
existed in the plant, and how they were there com- 
pounded, authors are not exactly agreed. Nor is it 
precisely known what part each plays in the life and 
health of the plant. There is good reason for believing 
that Iron is indispensable to the efficiency of chloro- 



32 CONCERNING A FEW 

phyll, and that the salts of Potassium have much to do 
with the production of starch. Besides the substances 
just mentioned, some compound of Nitrogen is essen- 
tial to the growth of plants ; and this is furnished like- 
wise through the roots. If, therefore, it is desired to 
have plants grow in a healthy and vigorous manner, 
they must not only be placed under the requisite phy- 
sical conditions, but good food in proper amount must 
be furnished. 

Plants, as we have already seen, obtain their carbon 
from the carbonic acid of the atmosphere. The soil 

furnishes other kinds of matter used as plant- 
fo*^~ food. Although the germinating seeds can thrive 

in sand for a while, it is because they can use 
the good store of food laid up for them by the plant on 
which they ripened. And, even after this store is gone, 
they will do pretty well for a time ; but sooner or later 
they need something better than sand to live in. Now 
sand is a very good mechanical support for sprouting 
seeds, if the seedlings are to be studied ; for it is the 
most cleanly. But, if the plants are to be raised from 
seed for the purpose of studying them in all their stages 
of growth, it will be better to procure some good soil at 
a florist's greenhouse. Flower-pots six or eight inches 
in diameter are large enough for the cultivation of such 
plants as are adapted to school-room study. In flower- 
pots of this size, it is perfectly easy, for instance, to 
raise good plants of Morning-glory to exhibit the twining 
movements of stems, and Sensitive Plant to demonstrate 
the " sleep," " waking," and sensitiveness. The plants 
may not prove to be as symmetrical as those raised by 
an accomplished florist ; but they will answer a good 



COMMON PLANTS. 33 

purpose in the school-room, for they are plants which 
the pupils have watched from the beginning of the 
growth. To show how small a part is taken in certain 
cases by the mineral constituents of plant-food^ it may 
be well to call to mind one of the earliest experiments 
upon the subject of vegetable nutrition.* Van 
Helmont placed in a proper receptacle exactly VanHei- 
two hundred pounds of carefully dried soil, and periment. 
then planted therein a willow, which weighed 
just five pounds. The soil was enclosed by a cover so 
that no dust from outside could reach it ; and it was 
kept moist with enough water as occasion required, for 
five years. At the end of that time, the willow was re- 
moved, and the soil separated carefully from the roots. 
The willow weighed then one hundred and sixty-four 
pounds ; but the soil, again thoroughly dried, as at first, 
had lost only two ounces \ Although the experiment 
was not conducted with the exactness which character- 
izes modern research, it was a very excellent one for 
the time in which it was performed. It must be added 
that Van Helmont erroneously concluded that the plant 
had taken all its nourishment from the water, whereas 
we know to-day that the plant obtains from the atmos- 
phere a large part of the material out of which its struc- 
ture is made. Before entering upon the use of plant- 
food in building, it is best to glance at the different 
ways in which a part of the elaborated substances are 
held in reserve. 

* From page 493 of Geschichte der Botanik, by Professor 
Sachs. The experiment was made about 300 years ago. 



34 CONCERNING A FEW 



VI. FOOD HELD IN RESERVE. 

We may speak of the carbon-dioxide taken from the 
atmosphere, the water from the soil, and the mineral 
matters therefrom obtained, as the food of the plant ; 
but it is better on all accounts to speak of the first 
elaborated matter formed in the foliage under condi- 
tions now described as the proper food for the nutrition 
of the plant. Some plants are like spendthrifts. They 
use up all this food as fast as it is made, and do not 
lay up much or even any of it. The annual plants 
treasure up a little of this food in the seeds, but plants 
which are to live through more than one year keep 
more or less food in reserve in some safe place. 

The food may be stored up as starch, as in most of 
the thickened fleshy roots and underground stems or 
branches, or in stems above ground, or even in 
starch, leaves. The starch is packed away in the form 
of an impalpable powder consisting of granules 
of such characteristic form that its source can be 
easily identified by the microscope. Sago and tapioca 
are starches which have been carefully separated from 
the substance of the plants which produced them, and 
the former has become somewhat changed by the pro- 
cess of manufacture. The laundry starches are largely 
from potato, or from wheat. Starch in woody stems 
like that of the maple in early winter is lodged in the 
less dense part, and here it is ready to be changed into 
syrup at the coming of spring. Starch can be very 
readily detected by the blue color which it gives when 
brought in contact with a dilute solution of iodine. 



COMMON PLANTS. 35 

Another very common form in which food is stored 
in reserve is sugar. This is its form in the stem of 
sugar-cane, and in the fleshy root of the sugar- 
beet. When sugar is properly made from these Sugar. 
two sources, it is impossible to distinguish be- 
tween them. Of the forms of sugar other than cane 
sugar, as it is called, nothing can now be said further than 
to point out their occurrence in fruits and exception- 
ally in stems. There are still other forms in which food 
is packed away in plants ready for use ; but their con- 
sideration would not be desirable in this short guide. 
It is enough to note now that the reserve material is 
packed safely, and when wanted it is within reach. 
And next it must be seen how it is used in building, or 
in growth. 

VII. PLANT-GROWTH IN GENERAL. 

Plant structure consists of minute cells of different 
shapes, variously arranged and compacted. Plant 
growth consists in the production of new cells, and 
their increase in size, at the cost of material prepared 
by foliage. 

Of course, this elaborated material must undergo 
many changes before it can be used for the building 
up of new cells. So far as shapes of cells are 
concerned, it is now necessary to refer to only sh ceiis.° f 
three principal forms : ist, spherical, or nearly 
spherical, these are generally compressed somewhat 
into polyhedrons by contact with other cells (as in the 
pith of Elder) ; 2d, elongated cells, which may be 
either cylindrical or spindle-shaped, that is, tapering at 



36 CONCERNING A FEW 

both ends (as in wood-cells) ; 3d, flattened cells of 
many sorts. 

When the wall of a cell is first formed, it is very 
delicate. In most cases, it speedily undergoes changes 

in its thickness and toughness. The thicken- 
wau. cell ~ m £ ^ s se ldom even. Its irregularities therefore 

give rise to dots and pits and pores, and 
many curious markings ; but these can be seen only 
under the microscope, and need not be further spoken 
of here. It is enough to observe now that the thick- 
walled cells in plants are generally of the second sort ; 
that is, they are elongated. They become sometimes 
very long and tough, and have only a small cavity, or 
none at all, within : these are called fibres. The other 
long thickish-walled cells, which are rather more brit- 
tle, are, with all their varieties, called wood-cells. An 
interesting form of wood-cell gives rise by its develop- 
ment to what are known as ducts. The cells are 
formed in chains, and the partitions between the cells 
break down, leaving a jointed tube or duct. Another 
very common form of wood-cell is spindle-shaped 
and flattened. 

To trace out the development of all these fibres and 
wood-cells, from the simple kind from which they rise, 

is a task wholly foreign to the present work. 
vvo b o r d- S cens d It i s enough to state that these cells, which 

in their varied forms give rise to the complex 
fabric of plants, are marshalled in definite order. Only 
a few of the more frequent modes of arrangement are 
now to be mentioned, and these only for the purpose 
of showing that a study of our common woods and 
barks, even without the aid of a lens, may be practi- 
cable in our schools. 



COMMON PLANTS. 37 

Plants which do not have woody stems are not at 
present to be considered. The herbs which have only 
very imperfectly formed wood, and the plants whose 
tender soft-wooded stems are killed by the frost, are to be 
left out of account. Any shoots of our trees or hardy 
shrubs with thick bark are available for illustration of 
the present subject. Willow, Poplar, Elm, Horse- 
Chestnut, Maple, or Ash will answer perfectly. If the 
newest part of the shoot is compared with that pro- 
duced two or three years before, it will be seen to differ 
in many respects. In the latter, the pith is less con- 
spicuous, there are other rings outside the first circle 
of wood, the bark has a firmer lining and a rougher 
exterior. Compare this older shoot with one which is 
five or more years older still, and the differences are 
more manifest. The outside layer is made up of a 
sort of cork which is beginning to crack here and 
there, giving to the bark a very irregular sur- 
face. This outer layer consisting of cork 
might be taken from the plant without any injury, if 
carefully done. The cork-bark of commerce, a very 
thick layer of this kind, is taken off from live trees of 
the Cork Oak in this way ; and then the trees produce 
another belt of cork, to be removed in a few years 
more. The number of years can be easily counted 
from their record in the compact layers. 

The inside layer of the bark consists of fibres which 
are frequently so conjoined as to form a kind of lace, 
fine in the lace -bark of the West Indies, 
coarse in our Linden. The fibres of Linden 
constitute bast-matting or Russia-matting. The fibres 
of hemp for cordage, of jute and flax ready for spin- 



38 CONCERNING A FEW 

ning, are bast-fibres which have been detached from 
the rest of the plant either by mechanical means, by 
chemical processes, or by what amounts to pretty much 
the same thing as the latter, decomposition. With the 
one marked exception of cotton, which consists of 
the plant-hairs on cotton-seeds, the textile fibres of 
the arts are bast-fibres. Indian Corn, Bamboo, and 
Rattan have their bast-fibres, with groups of wood- 
cells and ducts, scattered all through the stem, but 
ending for the most part at its very outside, here form- 
ing a dense cylinder not separable from the rest of the 
stem. In these cases, the distinct clusters of bast-fibres 
and ducts are packed firmly by means of spherical 
cells. The bast-fibres in the thicker leaves of plants 
of this sort — for instance, Century Plant and New 
Zealand Flax — are easy to prepare for use as cordage, 
&c, and they are strong and good. 

For the present purpose it may be said that the 
wood used in the arts is of two kinds, namely, that 
which consists only of wood-cells, properly so 
called, and that which has also ducts either 
large or small. The wood of the coniferous trees has 
no ducts, except sometimes at the very centre : it is 
made up of spindle-shaped cells, which are more or 
less flattened. Such woods as Oak, Ash, and Elm 
have proper wood-cells and ducts besides, in many 
instances the latter are very conspicuous, and give to 
the cross-section of the stem an open, porous look. 
Certain differences in the character of the wood-cells 
and the ducts, probably depending upon varying press- 
ure exerted by the bark, are observable between those 
formed in summer and in autumn. These differences 



COMMON PLANTS. 39 

are often clearly marked, and give rise to the well- 
known rings of wood. The thickness of the rings de- 
notes the amount of wood made during a single 
year. The new wood is made by the multi- ^™" e f 
plication of closely packed cells which lie be- 
tween the wood and the bark. These layers of closely 
packed cells have a double work. Upon one side 
they build new wood, on the other side they lay down 
a new him of inner bark or bast. In the spring, when 
these layers (the cambium or meristem) begin their 
work of forming new tissues, they constitute the juicy 
and sweetish substance found under the bark. The 
sweetness results from the presence of a kind of sugar 
which is made at that time from the stored-up starch. 
Removal of the cambium, of course, prevents the 
production of any more new wood or bast at the place 
of injury. Often, however, if the wound caused by its 
removal is not too grave, it may be healed over by thin 
films of freshly made cork. 

A very slight examination shows that the width of the 
year's wood varies considerably in different years, and 
on different sides of the stem. Moreover, the wood 
nearer the centre is denser than that just under the 
bark ; the former is the heart-wood, the latter is the sap- 
wood, and is the last formed. In some stems, the 
irregularities in the rings are very striking : in one case 
pointed out by President Chadbourne, the parts of two 
rings are sometimes confluent. Radiating from 
a point not far from the centre, many very S ^^ 
slender lines run in a somewhat broken manner 
out to the bark. These are the pith-rays. They lie 
between the wedges of wood, and, when they are seen 



40 CONCERNING A FEW 

in section, appear as shining surfaces. These consti- 
tute the silver-grain of wood. Here, then, are two 
things, each of which will look very differently in differ- 
ent slices of wood. Pieces of wood cut in different 
ways will be found to be frequently puzzling, but useful 
objects of study. The student is to identify the silver- 
grain planes, or the pith-ray lines, and to make use of 
these in connection with the circles of which they are 
radii, to ascertain certain facts respecting the speci- 
men. For instance, suppose a small prismatic block of 
wood, cut from an oak stem which is twenty inches in 
diameter : it will exhibit on its different sides different 
exposures of the rings, or cylinders, and the pith-rays, 
or planes ; and from an examination of these it will be 
possible to detect the place from which the block was 
taken. The difference in color between the heart- 
wood (the older) and the sap-wood (the newer), the 
differences in size between the inner and the outer 
circles, afford easy marks by which the position of the 
block with respect to the stem can be ascertained. If 
the plane sides of the block are not at right angles to 
each other, the problem becomes more difficult ; but 
it is always an interesting one. Questions respecting 
the position which a block or a board must have had 
in the log from which the piece has been cut will 
generally be found within the reach of most of the 
pupils except the youngest. 

The specimens * which have been furnished to illus- 

* Mr. Charles W. Spurr, 522 Harrison Avenue, Boston, 
prepared, for the purpose of illustrating the subject of Veneers, 
500 packages of excellent specimens of the following woods : 
Tulip-tree or Whitewood, Rosewood, Ash, Oak, Pine, Mahog- 



COMMOX PLANTS. 41 

trate the subject of texture of woods are known in the 
arts as Veneers. These are thin slices of wood, 
cut for the purpose of displaying the charac- Veneers, 
teristic texture or grain, and which are to be 
securely glued to cheaper woods. Specimens prepared 
in this manner exhibit very beautifully most of the 
features which have been referred to under the subject 
of circles and silver-grain. 

The branches which fall off from decay or are broken 
off by injury leave roughish projections, which sooner 
or later are healed over by the subsequent 
growth of the stem. The buried trace of the Knots. 
branch remains as a concealed knot, and fre- 
quently disturbs for a while the regularity of the wood 
formed in its immediate proximity. When the branches 
are small and exceedingly numerous, — especially if 
they are short and hard, as if the buds from which they 
sprang had given rise only to a blunt thorn, — the dis- 
turbance of the layers of wood produces some of the 
most beautiful of the ornamental woods. 

When the terminal buds of the main stem and of the 
branches of our trees expand fully for the season, their 
growth in length is arrested. The growth of the 
stem or branches in length in the following height. 
year is solely by the expansion of new buds. 
If two nails are driven into a stem, at a definite dis- 
tance from each other, that distance will ever afterwards 
remain the same. It must be remembered, however, 

any, Walnut, Butternut, Maple, Cedar, Birch, Cherry, Elm, and 
Holly. Many of these were in duplicate, exhibiting both plain 
and figured texture. The specimens, more than ten thousand 
in all, were gratuitously presented to the Class by Mr. Spurr. 



42 CONCERNING A FEW 

that the shape of a tree is constantly changing year 
after year, from the loss of branches, chiefly the lower 
and shaded ones, which do not have a fair chance ; 
and so the main trunk appears to carry the crown of 
branches higher and higher up. The relations of the 
position of buds to the ultimate shape of the tree, and 
of the relative strength and vigor of buds to the form 
at last attained, are easily observed with a little care. 
It is worth the while of any teacher to call attention to 
the spire-like and the spray-like forms of shade-trees, 
and to ask the pupils to compare the grown tree with 
its plan laid down upon a branch with buds. It is 
comparing a finished building with the sketch made 
before it was erected. 



VIII. THE FLOWER. 

A flower is a branch with leaves for the production 
of seeds. It is easy to find fault with every definition 
of so diversified a mechanism as a flower, but the defi- 
nition just given will answer our present purpose very 
well. On page 23, it is stated that, " since whatever 
springs from a bud is some sort of a branch, a flower 
developed from a flower-bud must be a branch too. 
And so it is. The helpful parts are here arranged in a 
very regular manner, and many of them are greatly 
changed in form and work." 

A blossom may be examined from many different 
points of view : of these, three will now be mentioned. 

1. A flower may be regarded as a complicated mech- 
anism made up of simple parts. Considered as a branch, 



COMMON PLANTS. 



43 



a flower must be looked upon as a very short one, 
with the leaves crowded together into circles 
or into much compressed spirals. First of all, Mor ^ 1 ' 
then, it is desirable to separate the parts of the 
crowded branch a little, so that their relations can be 
better seen. For this purpose, in ordinary cases, the 
following plate will be found useful. Begin with a 




Crassula, or some good regular flower, and place each 
part of each circle of the blossom in its corresponding 
place in one of the circles of the diagram. 

For instance, if the flower is on the plan of three, 
the parts of the outer circle (calyx) must be placed 
120° apart; the parts of the next circle (corolla) 120° 
from each other, alternating with the last ; the stamens 



44 CONCERNING A FEW 

come next ; and, lastly, the carpels, or the fruit-leaves 
(constituting the pistil) ; and the members of the cir- 
cles will have definite relations to one another. On 
the plan of five, the parts in one circle will be 72° 
apart ; on the plan of four, 90 . 

Now suppose we have a complete and regular flower 
with five members in each circle or whorl. Let the 
parts be separated, and placed in their proper order 
on the circles of the diagram, where they will again 
make up a complete and regular blossom. When this 
has been done, take away one of the stamens. Has it 
disturbed the relation of parts ? Obviously not : the place 
is left. Next break a stamen in quarters, and replace 
one of these fragments. It lies in its proper place a 
mere vestige of a stamen, but the relations of the parts 
remain the same. What we have thus done with the 
dissected flower, Nature has done with very many. 
How to see what parts have been lost, or what remain 
only as traces, is a very interesting study. This study 
becomes more difficult when the parts of one circle 
have become disproportionately enlarged on one side, 
or the parts of two circles have grown together more 
or less. To strip off these disguises, and detect the 
hidden symmetry of arrangement, is the attractive task 
of Morphology. 

For schools, the simpler flowers, of large size, are 
preferable at first. Dog-tooth Violets (Erytkronhim) , 

Lilies, Buttercups, Laurel (Kalmia), Single 
^ n fl a owers. P m ks, and so on, are good to begin with ; and 

these are to be dissected upon tablets, as above 
described, and as each part is removed it must go in 
its corresponding place. There is not an easier method 



COMMON PLANTS. 45 

of exhibiting the relations of position of the parts of 
flowers than the one here recommended. Even young 
pupils can remove the sepals, petals, stamens, and car- 
pels, — even if they have not been told the names, — 
and rearrange them in the proper order. After a while, 
let the names of the parts be given, and these will 
speedily become familiar. When practice in this has 
been sufficient, three questions are to be asked con- 
cerning every flower thus analyzed : — 

1. How many parts are there in each circle, and 
how are they arranged? 

2. How are the parts ef the same circle united to- 
gether ? 

3. How are different circles united? 

The study of flowers for the purpose of answering 
these questions may be made the best practice in obser- 
vation which Botany affords. The pupils must be made 
to understand that, at this period of their progress, no 
help is to be expected from the teacher : the answers 
must be found in the flower. To indicate how exhaus- 
tive and how far-reaching these three inquiries are, we 
will apply them to a single illustrative case. 1st, There 
are five sepals alternating with five petals ; five stamens 
opposite the petals, and none alternate with them ; 
more than one carpel, probably five, though the latter 
fact is hard to make out. 2d, The five sepals are 
united more than midway ; the petals are united to- 
gether, hence the corolla is monopetalous ; the stamens 
are separate ; the carpels are united to form a pistil 
with a single style and one-celled ovary with ovules in 
centre. 3d, The stamens are borne on the regular 
corolla ; the calyx, corolla, and ovary are all borne on 



46 CONCERNING A FEW 

the receptacle, and are distinct from each other. Now 
apply this to the Analytical Key of Dr. Gray's School 
and Field Book, and it will be found that we can, with- 
out hesitation, place the flower under the following 
heads : Flowering, Exogenous (plan of 5), Monope- 
talous, Calyx free from ovary, Corolla regular, stamens 
as many as the corolla-lobes and opposite them, style 
only one, ovary one-celled, ovules many = Order 
Primulacece. The facts elicited by the questions have 

been gained by the pupil in an analysis like 
fnaiys!s. d tnis by independent observation. If the 

pupil reverses this process, and uses the key 
in the Botany to ask the questions by, he is adopting a 
method which tempts one constantly to look ahead to 
see how " the plant is coming out," as the phrase is. 

If there is the slightest prepossession in the mind in 
regard to the probability as to which Order the plant 
belongs, this will influence the judgment about every 
point in the analytical key. It will lead, sooner or 
later, to a weak, careless, unfair, or even dishonest 
method of work. An analytical key is an artificial 
device at best, — a sort of pick-lock, to save time. 
It may be used after, but not before, the three ques- 
tions above spoken of have been answered ; certainly 
not while the questions are being answered. To study 
a plant and its blossoms, from the point of view of 
Morphology, is a task of such interest and value for 
training that it cannot well be overrated. To thread 
one's way through the mazes of an analytical key, before 
the structure of the flower in hand has been thoroughly 
mastered, is to deal with a puzzle of little interest and 
of less profit. 



COMMON PLANTS. 



47 



Another method of arranging the answers to the 
questions proposed on the basis of Morphology was 
suggested by Professor Henslow, and embodied 
in Professor Oliver's Elementary Botany. An Schedules, 
illustration will suffice : — 



Organs. 


No. 


Union of like Union op~ differ- 
Parts. I ent Circles. 


Calyx 

sepals 


1 gamo- or free from 
5 1 monosepalous ovary. 


Corolla 
petals 


5 


gamo- or 
monopetalous 


free. 


Stamens 


5 


distinct 


on corolla and 
opposite its 
segments. 


Pistil 

carpels 


5 


united 
together 


free from 
calyx. 


Seeds numerous, and on the axis. 



The blank schedule here filled out with the charac- 
ters of the Order Pritnulacea consists of the upper 
line, denoting the value of the several columns, and the 
left-hand column, in which the organs are enumerated. 
The blanks may be constructed in any way the teacher 
may choose, provided the answers to be written in 
filling them up bear upon the number and relations, as 
to position and union, of the parts of the circles of the 
flower. 

2. The second point of view from which a flower 
may be examined is that of Physiology. A flower is a 
mechanism for the production of seeds. All parts, 



48 CONCERNING A FEW 

therefore, which are directly concerned in the pro- 
duction of seeds, must be taken into account. 
l^gy! 10 " Even the floral leaves or bracts, which are only 
indirectly tributary to the formation of seeds, 
must be regarded. The outer circles, the calyx and 
corolla, are generally termed unessential, because they 
are frequently merely protective, while the stamens and 
the carpels are the essential parts. The carpels contain 
the ovules, which are to become seeds ; the stamens 
furnish the pollen, by the indirect action of which this 
change is to be brought about. Therefore, we might 
regard the ovules and the pollen as the only essential 
parts in the production of seeds. Each stamen con- 
sists of an anther, which is often supported upon a 
filament, or slender thread. " The anther is a sac 
filled with pollen, which most generally is like fine dust, 
but which is shown by the microscope to consist of 
minute grains of characteristic shape, size, and mark- 
ings. The pistil is made up of one or more carpels, 
distinct or more or less completely blended together, 
and usually comprises three parts : ( i ) the ovary, 
holding the ovules; (2) the style, surmounting the 
ovary ; and (3) the stigma, a point, or knob, or line of 
sticky surface at the side or summit of the style. The 
style may be wholly wanting. When the pollen 
Nation. acts u P on tne stigma, each grain may send 
down, after a time, a slender tube, which at last 
reaches an ovule. Here the contents of the tube act 
in some way upon the contents of a cell, or a group of 
cells, in the ovule, in which a new development begins, 
ending in the production of an embryo plant. The 
ripened ovule is a seed ; the ripened ovary, with its 



COMMON PLANTS. 49 

contents, and often with some of its contiguous parts 
adherent, constitutes the fruit." It would seem, there- 
fore, at first sight, as if flowers, in order to perfect 
seeds most readily, ought to be so constructed that 
the pollen can fall upon or reach the stigma without 
any difficulty. In some flowers, like the late and small 
flowers of our violets, and in a great many other cases, 
this is so : the pollen is placed by the anther directly 
upon the stigma, or the stamen is so placed that the 
pollen can very easily fall upon the stigma. But there 
are innumerable instances of just the opposite : and in 
these cases the transfer of the pollen must be made by 
the wind, by insects, or by some such agent. Some 
plants have the stamens only, while .others of the same 
species have only the pistils. Willows are good ex- 
amples of this kind of separation. Indian Corn is an 
example of a less complete separation. In this, the 
flowers with stamens form the plume above, and the 
pistils make up the ears with the silk (the styles and 
stigmas) below. The transfer of the pollen of Indian 
Corn is made by the wind, which can carry such dry 
dust to long distances. The pollen of some of our 
forest trees and shrubs is transferred by the same 
means, and it frequently falls by the way, collecting in 
large quantities on the leeward shores of lakes, where 
it resembles sulphur. There are many cases of sepa- 
ration of the stamens and pistil which are just as 
complete as Willow and Indian Corn, so far as the 
possibility of "the pollen reaching the stigma without 
help is concerned ; and yet the stamens and pistils are 
in the very same flower. For instance, in some orchids 
the pollen is packed away in a little pocket, from which 



50 CONCERNING A FEW 

it cannot fall to reach the stigma, but from which it 
is readily detached by the insect which comes to the 
flower in search of nectar. The insect unconsciously 
carries the package of pollen off to another flower, and 
here it is brought in contact with the stigma of that 
flower. These are among the most striking cases of 
complicated mechanism by which an end is reached, 
and they can best be understood by a careful study 
of Professor Gray's charming treatise, " How Plants 
Behave." Without engravings, which cannot be em- 
ployed in this guide, their further description is un- 
desirable. The object at present is merely to call 
attention to the interesting . field opened before every 
observer of flowers. The transfer, in many cases, 
must be made by insect aid ; but how can insects be 
made to work for something which does not concern 
them? There are a few insects which are pollen- 
eaters. Such, coming to flowers for the pollen they get, 
might scatter more or less pollen around, and transfer 
some of it from one blossom to another ; but there are 
more which are fond of the nectar of flowers. The 
nectar is for insects. It occurs in very diverse places 
in different blossoms, but it is almost always extensively 

and attractively advertised. Bright colors, with 
and fra- striking contrasts (the " nectar spot"), or with 

lines of contrasting color converging towards 
the cup of nectar (the " nectar guides"), show the 
insect visitors where their food can be found. A little 
attention will make clear the meaning of many of the 
colors which otherwise might be passed by without 
thought. There is hardly any phase of applied Mor- 
phology and Physiology in which pupils take more 



COMMON PLANTS. 51 

interest than the investigation of color in flowers, and 
the insect visitors. Among the very striking features 
to be noticed in regard to colors of flowers is the re- 
markable one that outside parts, the floral leaves or 
bracts, often share or even monopolize the brilliancy 
and attractiveness. 

Odors are in general indicative of the presence 
of nectar. The relations of color to fragrance, and 
both to the nectar which they advertise, will be 
found very attractive studies. Children can also be 
very intently absorbed by an unaided examination of 
the ways in which nectar is protected from injury by the 
rain. The keen-sighted German, Sprengel, who at the 
close of the last century first called attention to the visits 
of insects to flowers in their search for food, observed 
especially the modes of nectar protection. One of 
these ways, described in his quaint language, is here 
spoken of. This case possesses much interest, for it 
appears to have been the one which earliest attracted 
him to this branch of investigation. 

" When, in the summer of 1 787, I carefully examined 
the flower of Wood Geranium {Geranium sylvaticiwi), 
I discovered that the lowest part of its petals was pro- 
vided on the inner side and on both edges with fine, 
soft hairs. Convinced that the wise Author of nature 
has not made even a single hair without a definite de- 
sign, I reflected upon the purpose which these hairs 
might serve. And it then occurred to me that if we 
suppose that the five drops of nectar, secreted from as 
many glands, are designed for the nourishment of cer- 
tain insects, it might not be improbable that provision 
had been made to keep the nectar from injury by rain, 
and that these hairs are employed to attain this end. . . . 



52 CONCERNING A FEW 

Each drop of nectar rests on its gland immediately 
under the hairs which occur on the edges of two con- 
tiguous petals. Since the flower stands erect and is 
pretty large, it must catch rain-drops whenever it rains. 
But none of the drops which fall in can reach the 
nectar and mingle with it, for they are kept out by the 
hairs which cover it, just as the drops of perspiration 
which fall from the forehead are retained by the eye- 
brow and eye-lashes and kept from getting into the eye. 
And yet an insect is not hindered in the slightest from 
reaching the nectar. I next examined other flowers, and 
found that they had something in their structure differ- 
ent from the first, but which seemed to answer the same 
purpose. The further I prosecuted this investigation, 
the more plainly I saw that those flowers which possess 
nectar are so constructed that, although insects can 
easily get to it, the rain cannot injure it. Thereupon, I 
concluded that the nectar of those flowers is secreted 
chiefly for the sake of insects, and is protected against 
the rain so that they can enjoy it pure and uninjured." * 

It will also be found that children are greatly inter- 
ested in the group of phenomena known as the sleep 
sleep and and waking of plants, Flowers of some species 
Sowers °f Oxalis exhibit this very well under cultivation, 
and leaves. anc [ cou id b e systematically observed, only the 
waking takes place long before school-hours. In some 
instances, the closing of flowers, which are to open 
again, appears to protect the pollen from night 
dampness. It may be here noted that pupils who can 
visit such gardens and wild fields as are accessible near 
a large city, might with a little pains ascertain what 
plants open and shut their blossoms at given hours, 

* Das Entdeckte Geheimniss der Natur, 1793, p. 2. 



COMMON PLANTS. S3 

and what flowers close at the approach of bad weather. 
Facts like these brought to school, and fresh from the 
lips of the young observers themselves, possess a 
wonderful attractiveness for teacher and all the pupils 
alike. 

3. Flowers afford evidence of the degrees of kin- 
ship among the higher plants. The detection of the 
relationships belongs to Systematic Botany. 
Systematic Botanists rely upon the degree of Sy g e J^ 
resemblance as indicative of the degree of re- 
lationship ; but the features which they take into con- 
sideration are not generally those which strike the eye 
at first. Therefore, a deeper search must be made ; and 
the task is well adapted to a mature pupil, guided by a 
suitable hand-book of the principles of classification. 
But in our common schools this is impracticable. All 
that can be expected is to familiarize the older pupils 
with the systematic position of our common plants, as 
laid down in the Manuals of Botany ; and this should 
only be done by the course marked out under the first 
part of this section, p. 45. 

Comparison of allied species is always useful, and 
some practice may be given in the elements of de- 
] scrip tion. For the sake of acquiring the terms most 
readily, when the time has come for that, let the practice 
with fresh and dried specimens, and with such figures 
of plants as may be at hand, be thorough, but never 
tiresome. The mechanical execution of the chromo- 
lithographs of plants furnished the teachers in Bos- 
ton appears to be excellent ■ and the selections are 
generally good, especially those of the " Poisonous 
Plants." Good figures of plants can be turned to 



54 CONCERNING A FEW 

good account for this purpose ; * but they must never 
be used to the exclusion of fresh specimens or well- 
preserved dried ones. Pupils should be early 
p 1 r a e n s t e s r . ving taught to dry and preserve plants. This task is 
very simple, and the collections are rapidly and 
easily made. Any common unglazed paper, like news- 
paper, will answer. 

" In laying out the specimen for the press, use 
plenty of paper, so that their moisture may be quickly 
absorbed, and the danger of mould avoided. The 
specimens should be laid between the sheets of drying 
paper in as natural a position as may be, taking care 
not to crumple the leaves or flowers. If the specimens 
be too long for the paper, they may be carefully folded 
or cut in two. Delicate flowers should be carefully 
folded in paper when gathered, and kept flat. Do not 
arrange all the specimens just in the middle of the 
paper, but dispose them in such a way that, were a pile 
of them in their papers two feet high, they would not 
topple over : this will equalize the pressure. Several 
dry sheets ought to be laid between each layer of fresh 
specimens, the quantity of paper depending upon the 
thickness and succulence of the plants to be pressed. 
Pasteboards, or, better still, ventilators — made the size 
of the paper, of narrow strips of very thin pine wood 
(1-16 inch) at short distances apart, nailed together in 
two layers at right angles to each other — may be intro- 
duced at intervals between the layers of paper until the 
pile be ready for the press, which may consist simply 
of two stout boards, made so that they cannot bend or 
warp. 

* A work by Professor T. Meehan, " Native Flowers and 
Ferns," contains many excellent plates, exhibiting the foliage 
and the general habit of the plants. 



COMMON PLANTS. 55 

" Between these boards the paper and specimens must 
be placed, and a weight of stones or metal, not less than 
50 or 60 lbs., laid upon the top. 

" The papers should be changed several times once 
a day, and then at longer intervals, until the specimens 
are quite dry, when they should be removed from the 
press. If fresh specimens be placed in the press, while 
others are in process of drying, they must be carefully 
separated by pasteboard or by a thick layer of paper. 

" The length of time which specimens ought to 
remain in the press varies with their nature, whether 
dry or succulent, and with the kmd and quantity of 
paper used."* 

One of the most successful preparers of specimens 
of dried plants has frequently said to his friends that 
" specimens are made or spoiled in the first twenty- 
four hours ; " that is, the papers should be frequently 
changed, or as often as they become damp, during the 
first day. 

When dried specimens of flowers are carefully soaked 
in warm water, the parts become so softened that they 
may be readily dissected. It is just about as easy, 
though not quite so interesting, to study dried speci- 
mens thus soaked, as it is to study fresh ones. Even 
the hastily gathered specimens which one collects 
during a rapid journey, and thrusts for preservation 
between the pages of a book, can be soaked out, dis- 
sected, studied, and named at the first leisure. 

* Professor Oliver's Elementary Botany, p. 288. 



56 • CONCERNING A FEW 

IX. FRUITS AND SEEDS. 

The ripened fruit-leaves, with their contents, consti- 
tute the fruit. But, in maturing, it is often the case that 

some other parts grow ripe too, and, clinging 
Fruits. to the fruit proper, are to be regarded as a part 

of it. For instance, a strawberry is mainly a 
pulpy receptacle upon which are dotted the true fruits 
which look so much like seeds. This is not the place 
to classify or enumerate fruits ; but a few words respect- 
ing some of the more common kinds may not be amiss. 
When the carpel or carpels ripen into fruit, the latter 
may open at maturity, or it may remain closed. The 
opening sorts are poas of many kinds, capsules, and so 
on : the closed sorts are the berry, in which the whole 
ovary ripens into a pulpy mass with a thin or thick* skin ; 
the stone-fruit, with a hard bony or stony shell, in which 
the seed is the shell, usually covered with a fleshy or 
fibrous mass, as in the peach and the almond ; the 
nut, which has an extremely tough integument ; and 
akenes, or achenia, which are one-seeded and dry fruits, 
usually small. Owing to the singular but not very deep 
disguises which the pistil takes on during its ripening 
into fruit, it affords a most excellent object of study by 
young scholars. They can watch the changes in an 
apple-blossom, for instance, and detect the character 
of the modifications which occur after the petals have 
fallen and the fruit begins to form. The range of fruits 
at the command of the teacher in a city is pretty wide, 
and yields material which may be utilized, not merely 
for talks which will be interesting, but for solid study 
which must be profitable. 



COMMON PLANTS. 57 

Within the fruit are the seeds. An exception, which 
may be mentioned in passing, is found in the Conifers, 
including the Pines, Spruces, and so on, which 
have seeds, but do not possess any closed pis- Seeds. 
tils ; and so, according to the definition, cones 
are hardly to be called fruits. The seeds in fruits 
which remain closed are not furnished with any inde- 
pendent means for dispersal : here the dissemination is 
effected, if at all, by the fruit in some way. Bui the 
seeds of fruits which open at maturity are not infre- 
quently furnished with wings, plumes, and hairs, upon 
which they can be carried in the air for considerable 
distances. Many of the one-seeded fruits 
which do not open when ripe have means for Nation" 
dissemination, such as wings, plumes, and hairs, 
like the seeds spoken of; and others have grappling- 
hooks, claws, teeth, and so on ; while some of them 
are so constructed that they can be fastened securely 
in the ground when they have found a good place. 
A good case of this has been described by Hanstein.* 

" Each of the pods or valves of Er odium is pretty 
long, roundish near the base, where it is fastened by 
a point. At maturity, the outer side of each contracts 
by drying more strongly than the inner, and thereby 
causes an outward curvature and separation of the parts 
of the fruit. But, the tissue of the awn or prolonga- 
tion of the pod being hygroscopic, it extends again by 
absorption of moisture from the air. On further dry- 
ing, the awn by more complete contraction on one side 
rolls up to form a perfect screw, whilst only the upper 
extremity bends out into a sickle-like curvature. If the 
fruit is fastened perpendicularly on a support, the 

* Botanische Zeitung, 1869, p. 530. 



58 CONCERNING A FEW 

curved end moves like the hand of a watch, sometimes 
backwards, sometimes forwards, with every change in 
the amount of atmospheric moisture, and on this de- 
pends the well-known application of these fruits in the 
construction of simple hygroscopes. The very large 
fruits of Mr odium gruinum are especially adapted for 
this study. When drying, the fruit forms a left-handed 
screw, so that with increase of moisture the tip turns 
like the hand of a watch ; by diminution of moisture, it 
goes the other way. If such a fruit is put in a fresh 
and therefore extended state on soil which is not too 
moist, the tip of the beak will describe at first a broad 
lateral sickle-like curvature, while in its lower part twist- 
ing begins. Supported on the curved upper end, the 
fruit rises and by means of its point gains a position 
which is inclined to the ground. By increasing tor- 
sion, it therefore penetrates the soil, and straightway is 
fastened there, for it is wholly covered with little bristles 
which, being directed somewhat up, act like grappling- 
hooks. By further spiral movement, the fruit goes more 
deeply into the ground, since the end of the awn fixed 
in a slanting direction against the ground can neither 
penetrate it nor yield. While thus one turn follows 
another, the spiral nearest to the head of the fruit bores 
into the ground like a cork-screw, and pushes the true 
fruit before it and more deeply down." 

The fruits of our cultivated Pelargonium exhibit nearly 
the same phenomena. 

The good of wide dissemination is easily understood. 
It enables the embryo plant in the seed to have a 
better start in life than if it had to grow up under the 
shade of, and in rivalry with, the plant which produced it. 
In one very striking case, the seeds are furnished with 
hairs which are turned to great account in the arts. 



COMMON PLANTS. 59 

Cotton consists of the plant-hairs found thickly packed 
upon the seeds of Gossypium. This plant-hair is the 
only one which has yet been sucessfully used in spin- 
ning. 

Regarding the useful products from the vegetable 
kingdom other than those already mentioned, very little 
can now be said. In almost any of the treatises 
mentioned on page 10, teachers can find in- S f°™ e p rocL 
formation respecting these : such as Rubber ucts ] ^ 1 ° t ^ 1 
from the milky juice of many plants ; Opium, 
the concrete milky juice of the unripe capsules of the 
Poppy ; Cocoa from the seed of Theobroma ; Tea from 
the leaves of a species of Camellia / Coffee, the seed 
of a subtropical tree ; and so on. 



X. MOVEMENTS, AND PARASITISM. 

It remains now, in closing, to call attention to a few 
curious vegetable phenomena which always excite the 
interest of pupils : ist, Movements. These 
may be (i) chiefly mechanical, as in the dried move- 
parts which change form and move, when 
water is applied. The " Resurrection Plant " of Cali- 
fornia, and the Erodium, p. 57, are good illustrations 
of this. (2) The spontaneous movements of twiners 
like Morning-glory and Hop-vine ; (3) movements 
after touch or shock, as in the case of the Sensitive 
Plant. These are clearly described in " How Plants 
Behave." All the moving plants there spoken of can 
be cultivated with a little care in school-rooms. 
2d. The insectivorous plants, especially Dro- J^^zaxs 
sera, can be grown with facility at any ordinary 



60 CONCERNING A FEW 

school-room window, and many of the phenomena 
described by Mr. Darwin in his " Insectivorous Plants" 
can be examined by the pupils. The tentacles of- 
Drosera can be seen to bend over and down upon the 
prey which they sooner or later consume as food. 

Lastly, attention should be called to the fact that 
many plants have no leaf-green (p. 29), and there- 
fore have to depend upon other organisms 
plants. 110 f° r nutriment. They are generally white or 
whitish. 

" There are some parasites which obtain only a por- 
tion of their nourishment thus at second-hand : they 
possess more or less leaf-green, and are able to assimi- 
late inorganic matter ; but, at the same time, they 
attach themselves to the stems or roots of other plants 
and absorb elaborated juices from them. Such plants 
are called partial parasites. There are several species 
belonging to the Figwort family, in which this partial 
parasitism has been clearly demonstrated. As in the 
case of the Gerardias, the foliage is green, and the 
appearance of the plants does not suggest that they 
are obtaining any of their food in a surreptitious man- 
ner. A few of the roots become attached to the roots 
or underground stems of other plants, and draw from 
them elaborated nourishment." * 

The parasites, just referred to, have flowers and pro- 
duce true seeds ; but by far the largest number of para- 
sitic plants and of saprophytes belong to the lower 
groups which produce no seeds with embryo plants 
therein. These lower plants are termed Mushrooms, 
Moulds, and Rusts. It is in these latter groups that 

* Sprague's Wild Flowers, p. 15. 



COMMON PLANTS. 6 1 

the lower confines of the Vegetable Kingdom are 
reached. Such simple organisms, the yeast-cells, for 
instance, so far as the food is concerned, have so much 
in common with animals, that some naturalists have 
placed them in a middle kingdom between the vegeta- 
ble and animal worlds, for they have some characters 
of both. At any rate, these lower plants, devoid of leaf- 
green, hide from view any sharp line of demarcation 
between plants and animals. 



Cambridge : Press of John Wilson &■» Son. 



